Diaphragm pump



J. w. swam-a 038,089

DIAFHRAGM PU MP Filed March 14, 1932 2 Sheets-Sheet l Patented Apr. 21,1936 PATENT OFFICE DIAPHRAGM PUMP John W. Smith,

Application March 14,

3 Claims.

This invention relates to high pressure metering of liquids and, moreparticularly, to the metering of liquid fuel for internal combustionengines.

The primary object of my invention is to provide a novel meteringmechanism, herein shown as applied to a new form of diaphragm pumpingelement, which is suited for high pressure metering of liquids, such aswater or gasoline, that lack sufficient lubricating properties to bemetered by the precision tted pistons of conventional pumps.

My novel diaphragm pumping unit has been operated at speeds above threethousand strokes per minute.

Precision metering is obtained by my invention at all speeds, due to thefact there is no leakage, While a novel diaphragm arrangement is madeuse of.

It is to be noted the diaphragm is preferably made of flat temperedspring steel which may be of the stainless variety. The amount ofiiexing imposed on the diaphragm is exceedingly small. A at disc one andone-eighth inches in diameter would have a flexing movement of eightonethousandths of an inch on Veither side of the neutra] position. Thecombined pumping movement for two diaphragms would be .032 producing adiaphragm iiexing of .008.

My improved metering mechanism has a novel mechanically-operated valveplunger which also actuates the pumping element.

For the purpose of illustrating my invention, I have shown by theaccompanying drawings an embodiment thereof which will be found inpractice to give satisfactory and reliable results. It is, however, tobe understood that the various instrumentalities of which my inventionconsists may be otherwise arranged and organized, and that saidinvention is not limited to the precise form as herein shown anddescribed.

In the drawings:

Fig. I is a central vertical section through a diaphragm pump embodyingmy invention.

Fig. II is a similar section of the diaphragm pumping unit, andassociated parts, drawn to a larger scale; and,

Fig. III is a top plan view of the upper portion of Fig. I, drawn to areduced scale.

Referring more in detail to the drawings, the cam shaft 4 is mounted ina housing 5 on suitable anti-friction bearings 6, one only of which isshown. The pump casing 1 is bolted tov the cam housing 5 by suitablebolts 8one of which is shown in Fig. I. A roller 9 is journaled on aPhiladelphia, Pa.

1932, Serial No. 598,655

pin i0, which is securely mounted in a slide II, reciprocative in theguide I2 that is securely clamped into the casing 'I by appropriatebolts, not shown. The diaphragm I3 and metering nut I4`are also clampedin place by the aforesaid 5 bolts. The reciprocating valve member orplunger I5 has a threaded portion for clamping the diaphragm I3 theretobetween special washers I6 and I'I.

A spring I8 under compression is the means for 10 causing the roller 9to follow the eccentric p0rtion of the cam shaft 4, as shown at I9.V Thediaphragm I3 ilexes to either side of its neutral position and preventsthe mingling of liquids in the pump casing I and housing 5. An ad- 15juster screw stop 20 is threaded in the nut I4 around the valve memberI5, while a gear 2I is securely fastened to set screw 20 and meshes witha pinion 22. A shaft 23 is secured to the pinion 22 and is rotatable bya lever 24 keyed 20 to said shaft by means of a key 25. Fig. III showsthe movement of the lever 24 to be from point 26 to point 21. When thelever 24 is at point 21, there would be no movement of pumping element28, but the maximum movement of 25 such pumping element is obtained whenthe lever occupies the position 26 shown in Fig. III.

In Fig. I, valve plunger I5 has raised the pumping element 28 a distanceequal to the gap 29, which represents a normal pumping move- 30 ment. Itis obvious that the adjuster screw 20 may be turned to bear hard againstthe spring loaded valve seat partV 30, thus eliminating the gap 29 andpreventing any pumping movement. This condition would take place whenthe lever 35 24 is at point 2l.

In Fig. I, diaphragms 3I and 32 are shown to be fully exed inwardstoward one another and all of the liquid has been expelled throughspring loaded ball valve 33. 40

In Fig. II, diaphragms 3I and 32 are shown reversely exed to the maximumpoint for taking in a full charge of liquid. To permit this, the lever24 would be stationed at 26 in Fig. III. The corresponding downwardmovement of part 15 28 has closed the gap at point 29 between the parts28 and 20, shown in Fig. I. A further downward movement of valve plungerI5 has withdrawn its conical end from valve seat 34, thus openingcommunication between the pas- 50 sage 35 and the orifice or passage 36.3l is a restricted circumferential passage which may have an opening ofless than .002, measured in a radial direction, which serves to strainentering liquid. This straining of the liquid is an impor- 55 the pumpcasing 1.

tant detail requisite to prevent grit and foreign particles from lodgingon the valve seat 34 or entering the diaphragm cavity.

Diaphragms 3l, 32 and annular ring 38 are clamped and secured in aninternally shouldered and screw threaded sleeve housing 39 withconsiderable pressure on their outer edges or margins by means of atubular nut or externally threaded sleeve 40 whose inner end forms aninternal shoulder in the housing 39, opposite its own internal shoulderalready mentioned. The faces of annular ring 38 and washers 4I, 42 aremachined to an appropriate angle or bevel to permit the requisitediaphragm deflection to each side of its neutral position.

In Fig. I it will be noted the diaphragms 3 I, 32 have been defiectedhard against the annular ring or spacing sleeve 38 by washers 4I, 42.The diameter of the washers 4I, 42 is larger than the bore of theannular ring 38, so that they overlap the diaphragms 3l, 32 outwardsubstantially to the housing parts 39, 40. A comparatively large washeris very important in preventing the substantially flat flexible annulardiaphragms 3I, 32 from -deiiecting beyond a predetermined point duringthe pumping period when the liquid is under maximum pressure, which maybe as high as 4000 pounds per square inch. Bolts having specially formedannular heads 43, 44, with their under sides machined to the requiredbevel or angle, limit the inward flexing of the diaphragms 3l, 32 to therequisite amount. Diaphragms 3l, 32 are clamped and secured withconsiderable pressure on their inner edges or margins between the headsof bolts 43, 44 and washers 4I, 4 2. The bolts 43, 44 serve assupporting and operating connections, respectively, for the diaphragms3|, 32.

Referring to Fig. I, compression spring 45, which is arranged aroundhousing members 39, 40 and acts on a shouldered ring of valve seat part30 into which operating bolt 44 is screwed fast, so that the valve seatpart 30 is really part of the diaphragm operating connection, has exeddiaphragms 3I, 32 to the position where metering of the charge of liquidtakes place. A plug 46 is threaded into the pump casing cover plate 1.The packing unit 41 has a recess for inserting packing 48 for thepurpose of preventing liquid from leaking past the threaded portion ofthe plug 46. 49 is a locking device for the plug 46 and is held in placeby bolts 50.

Fig. I shows the cam shaft 4 to have moved valve plunger I5 to the endof its instroke or pumping movement. At this point the plug 46 isadjusted to 'establish maximum deflection of the diaphragms 3| and 32.The valve seat 5I for the ball valve 33 is clamped in place by a nut 52,while said ball valve is held to its seat by a tension spring 53. Thenut 5.2 is suitably threaded for connection of a conventional pipefitting, as ordinarily used with spray nozzles for internal combustionengines. The bolt 44 has the fuel orice 36 extended as an axial passagethrough its center; while the bolt 43 has a passage 54 with right angleturns which is an important feature in expelling the air when the pumpis first started.

An orifice 55 is threaded for a suitable pipe connection through whichthe liquid enters into A pressure of five pounds per square inch aboveatmosphere is required to force the liquid into the pump through thecircumferential strainer passage 31. If the liquid is sluggish and thestrokes per minute are high,

considerably more pressure would be necessary. In Fig. I, 56 is abushing for mounting the shaft 23, and it is provided with an anti-leakpacking 51; while the shaft 23 is held in place by a spring 58. 59 is asleeve against which the upper end of the compression spring 45 abuts,said sleeve being held in place in the pump casing 1 by the cover 1thereof.

In operation, the rotation of the cam shaft 4 causes reciprocation ofthe slide II and of the valve member I5, the length of their strokecorresponding to the distance I9. At each upstroke, the valve member I5strikes the valve seat 34 in the member 30 and lifts it off the stopscrew 20 a distance corresponding to the vertical position of the screw:i. e., a maximum distance 29 equal to half the stroke I9 when the lever24 is at 26 in Fig. III and the s crew 20 at its position in Figs. I andII, and a distance of Zero when the screw 20 is adjusted a distance 29above its position in Fig. I, with the lever 24 at 21 in Fig. III.During the downstroke or outstroke of the valve member I5 and of themember or connection 30, a partial vacuum is created in the spacebetween the separating diaphragms 3l, 32; and when the connection 30 isarrested by the screw 20 and the still descending valve member I5 drawsaway from its seat 34, then liquid fuel is drawn in through strainerpassage 31 and passages 35 and 36 into the space between the diaphragms3|, 32. When valve member I5 rises again and closes against its seat 34on member 30, its further rise raises member 30, brings diaphragms 3l,32 closer together, and forces out a corresponding metered amount ofliquid from between diaphragms 3l, 32 past ball valve 33,- this amountbeing determined by the adjustment of the lever 24 and screw 2U.

It will, of course, be readily understood that various changes may beeffected in the details of construction within the scope of my inventionas defined by the following claims.

Having thus described my invention, what I claim is:

1. A pump unit comprising a housing with a pumping bore therein;opposedly-flexible spaced diaphragms sealing said bore;relatively-reciprocative displacement means including rigid annuloutwardly-overlapping the pumping bore and effective to prevent thediaphragms from being flexed by hydrostatic pressure; said sealingdiaphragms being respectively secured between opposedly-inclinedconfronting faces to the relatively-recipro'cative means near thecenter, and similarly at their outer peripheries in the housingaforesaid; one of the displacement means having an induction passagecommunicating with the pumping bore, and the other a valve-controllededuction passage; means for straining liquid entering the inductionpassage; and means, including a valve controlling said inductionpassage, for reciprocating the first mentioned displacement means.

y2. A pump unit comprising a housing with a pumping bore therein;opposedly-flexible spaced diaphragms sealing said bore;relatively-reciprocative displacement means including rigid annuloutwardly-overlapping the pumping bore and effective to prevent thediaphragms from being flexed by hydrostatic pressure; said sealingdiaphragms being respectively secured between opposedly-inclinedconfronting faces to the relatively-.reciprocative means near thecenter, and similarly at their outer peripheries in the housingaforesaid; one of the displacement means having an induction passagecommunicating with the pumping bore, and the other a valve-controllededuction passage; means for straining liquid entering the inductionpassage; a reciprocatory plunger for actuating the rst mentioneddisplacement means and having a valve portion controlling the inductionpassage; and adjustable stop means coacting with the inductiondisplacement means to vary its outward movement.

3. A pump unit comprising a housing with an annulus therein providingthe pumping bore, said annulus having beveled ends confrontingopposedly-inclined shoulders alforded by the housing;

relatively-reciprocative displacement means in' the form of headedmembers with coactive rigid washers, the heads of such Washers beingsubstantially conformative with, and the rigid Washers extendingoutwardly beyond, the pumping bore; opposedly-exible diaphragms adaptedfor sealing the pumping bore, said diaphragms being respectively securednear the center between the inclined face of a rigid washer and theopposedlyinclined underface of the associated headed displacementmember, and similarly at their outer peripheries between the annulusbeveled ends and the housing shoulders aforesaid; one of thedisplacement members having an induction passage communicating with thepumping bore, and the other a valve-controlled eduction passage; meansfor straining liquid entering the induction passage; a reciprocatoryplunger for actuating the first mentioned displacement member and havinga valve portion controlling the induction passage; and adjustable stopmeans coacting with the induction 4displacement member to vary itsoutward movement.

JOI-IN W. SMITH.

